title: Note: a latched comparator circuit for triggering continuous-wave cavity ring-down spectroscopy.
abstract: Continuous-wave cavity ring-down spectroscopy offers several advantages over cavity ring-down spectroscopy with a pulsed laser, such as a higher repetition rate and decreased cost. However, the continuous-wave technique requires a more complicated experimental setup because the laser must be switched off rapidly when the intensity is high in order to observe a ring-down event. This note describes an inexpensive and simple latched comparator circuit that can be used to detect light intensity above a threshold value and send a signal to rapidly steer the beam out of the cavity and initiate a ring-down event. The latch eliminates switching noise by preventing the comparator from switching during the ring-down event.
authors.affiliation: Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff Street, Northridge, California 91330-8262, USA.
authors.forename: Abdur
authors.initials: A
authors.lastname: Rasheed
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Curtis